Expansible bit



G. N. FITCH 1,804,681

EXPANSIBLE BIT Filed May 6. 1950 2 Sheets-Sheet l May 12, 1931. I

@MMMQ 4 ATTORNEYS O M 6 5 w m v Q Y B Patented May 112, 1931 GEORGE I\T. FITCH, OF VENTURA CALIFORNIA EXPANSIBLE BIT Application filed May 6, 1930. Serial No. 450,168.

This invention relates to an expansible bit I comprisin cutter carriers fulcrumed in the body so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position and an axially movable mandrel to expand and collapse the carriers. An object of this invention is to provide an expansible bit of the character described having a mandrel which is movable or advanceable in one direction for expansion. and collapsion. Another object of this invention is to provide a mandrel which may be advanced hydraulically. A further object of this invention is to provide a mandrel and trigger mechanism releasable by a plummet to enable collapse ofthe carriers. A still further object of this invention is to provide an expansible bit of the character described having a novel type of mandrel to coact with the cutter carriers.

These objects together with other objects n and corresponding accomplishments are ob tained by means of the'embodiment of my invention illustrated in the accompanying drawings, in which':

Fig. 1 is an axial section showing a bit with parts in initial collapsed position; Figs. 2, 3,

elevation and the parts being in expanded and 4, are sect'ons as seen on the lines correspondingly n mbered in Fig. 1; Fig. 5 is a fragmentary side view showing a cutter mounted upon a carrier; Fig, dis a section through the bit, the mandrel being shown in not limited to any particular number of cutter carriers. On the exterior of the body are longitudmally extending recesses to accommodate clrculation and these are marked 13 and best shown in. Fig. 4. The recesses extend from the head portion of the body marked 10a to the lower end. In. the slots 14 are cutter carriers comprising arms 15 pivoted intermediate their ends on pins 16 extending transverse to the drilling axis of the bit. Pinned to the lower ends of the carriers are cutters 17. However, it will be apparent that any suitable type of cutter may be used, and if desired, the carriers and cutters may be made integral; The inner faces of the carriers are spaced from one another to accommodate a mandrel. The inner faces slope from the pivot axis so that suflicient clearance is provided for swinging ofthe cutters without interference by the mandrel. At the upper end of the carriers is a cavity18 formed by opposing recesses. Below the pivot. pin 16 is a cavity 19 formed by recesses, and the carriers are cut away to provide a third and lowest cavity as indicated by 20.

The'head end of the body has a bore in which is slidably mounted a telescopic'tubular sleeve 21. This sleeve has its wall slotted at diametrically opposite points and pivotally mounted therein are trigger fingers 22. The lower ends of the fingers are squared and adapted to rest upon a seating shoulder or ledge '23 as shown in Figs. 1 and 6. The upper inner ends of the fingers are bevelled as indicated by 24 to permit a go-devil or plummet to pass between them to the position shown in Fig. 7. An arresting shoulder 25 is provided in sleeve 21 for the go-devil which is marked 26 in Fig. 7. The bore of the connector sleeve is reduced in diameter at 27 to be engaged by an enlargement on the mandrel. In the wall of' sleeve 21 are. perforations 28 for registering with an annular roove 29 from which extend ducts 30 leadmg to circulation passages 31. Circulation passages 31 extend from the bore in the head at the ports 32 to the lower end of the body adjacent the cutters. The ports 32 are so situated, that when the connector sleeve is in its upperposition as shown in Figs. 1 and 6, the ports are closed and when the connector sleeve is in the lower position shown in Fig. 7, the ports 32 are Open to circulation passing from the drill pipe. When the connector sleeve is in its upper be inserted in the well.

position as shown in Figs. 1 and 6, the perforations 28 register with the annular groove 29 so that circulation may passthrough the ducts 30 to the circulation passages 31.

The mandrel consists of a tubular member 33 with an enlargement 34 at the upper end to coact with the seat 27 in the connector and a valve seat 35 at the lower end for a ball check 36. On the mandrel is an upper head 37 and a lower head 38. These heads are of bull nose formtapering at their lower portion and are of such overall dimensions, as to fit within the cavities 18, 19 and 20.

The heads 37 and .38 are so spaced that, when head 38 is in cavity 19, head 37 is in cavity 18 with the carrierscollapsed as shown in Fig. 1, the upper head 37 clearing the carriers. When the mandrel is lowered to the position shown in Fig. 6, the head 38 is'disosed between the carriers and the head 37 18 disposed in the upper cavity 18 clearing the carriers. This causes expansion of the carriers. In the positionvshown in Fig. 7, the mandrel has'been still further advanced, and the head 37 is between the carriers, while the lower head 38 is clear of the carriers and rests in cavity 20. In this position, the upper head will have expanded the carriers.

1 The operation of the bit is as follows: initially, the connector sleeve 21 is disposed in the position shown in Fig. 1 with trigger fingers 22 disposed on the annular seat 23. Leaf springs on the fingers tend to maintain the latter in their retaining positions. It is obvious, that the connector sleeve will then be held against downward movement. The mandrel 33 is then positioned with the lower head 38 in the intermediate cavity 19 and with the upper head 37 clear, the enlargement 34 being disposed so that the mandrel may have a limited. downward movement. The cutter carriers are collapsed, and the bit may When the bit has reached the position at which it is desired to drill, circulation is started down through the drill string. Prior tothe starting of circulation, any liquid which is in the well hole may have passed upwardly by the check valve 36. As circulation is inaugurated. the check valve 36 is closed and the hydraulicpressure will cause the mandrel to be advanced to the position shown in Fig. 6. In this position the cutters are expanded. The delivery of circulation fluid to the cutters is provided for by the perforations 28, annular recess 29, branch ducts 30 and circulation passages 31. The bit may now be turned to drill. When it is desired to pull the bit from the hole, a godevil is dropped into the bore of the drill string and passes downwardly. The nose of the go-devil 26 as shown in Fig. 7, enters between the trigger fingers and swings the latter so as to release them from the seating ledge 23. The go-devil next strikes the shoulder 25 and forces the connector sleeve to its lower position. In its movement downwardly, it engages the upper head 37 and forces the mandrel down to collapsed position as shown in Fig. 7. Circulation may now be continued by way of the ports 32 which have been uncovered. The bit in collapsed position may then be pulled and on insertion in the well hole again, the parts are placed in the position shown in Fig. 1.

What I claim is 1. An expansible bit comprising a slotted body, cutter carriers fulcrumed in said slots transverse ofthe drillingaxis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads, a cavity formed between said carriers below their fulcrums to accommodate the lower head, said heads being spaced in relation to said carriers so that with progressive advance of the mandrel towards the lower end of the body the lower head is disposed in said cavity to enable collapsion of the carriers, then the lower head is disposed between said carriers to expand said carriers, and next the lower head is cleared of said carriers and the upper head is disposed between said carriers to collapse the latter, and means to advance said mandrel.

2. An expansible bit comprising a slotted body, cutter carriers fulcrumed in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads, spaced cavities formed between and'by said carriers below the fulcrums of said carriers to accommodate the lower head, said heads being so spaced with relation to said carriers that with progressive advance of the mandrel toward the lower end of the body the lower head is disposed in the upper cavity to enable collapsion of the carriers with the upper head clear of said carriers, then the lower head is disposed in a cavity between said carriers to expand saidcarriers and with the upper head clear of said carriers, and next the lower head is disposed in the lower cavity and the upper head between said carriers to collapse the latter, and means to advance said mandrel.

3. An expansible bit comprising a slotted body, cutter carriers fulcrumed in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads, spaced cavities formed between and by said carriers, one each to accommodate a head, said cavities being spaced with relation to said heads so that with progressive advance of the mandrel toward the lower end of the body the lower head is disposed in a cavity to enable collapeating with said bore, a check valve controlsion of the carriers with said upper head ling-said passagetoprevent outflow of liquid,

clear of said carriers, then the lower head is a cavity formed between said carriers below disposed out of said cavity between said cartheir fulcrulns to accommodate the lower 5 riers and below their fulcruins and the uphead, said heads being spaced in relation to 4 tion and inwardly to collapsed position, an

said cavities being spaced with relation to of said carriers to enable collapsion of the communicating with said bore, a check valve I per head is disposed in a cavity to expand said carriers, and next the lower head is disposed in a cavity and theupper head out of a cavity and between said'carriers and above their fulcrums to collapse the latter, and means to advance said mandrel.

4. An expansible bit comprising a slotted body, cutter carriers fulcrumed in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung outward ly to expanded position and inwardly to collapsed position, and axially movable mandrel having upper and lower heads, three spaced cavities formed between and by said carriers to accommodate said heads, the two lower cavities being contiguous, said cavities being spaced so that with progressive advance of the mandrel toward the lower end of the body thelower head is disposed in the intermediate cavity to enable collapsion of the carriers and the upper head clear of said said carriers so that with progressive advance of the mandrel toward the lower end of the body the lower head is disposed in said cavity to enable collapsion of the carriers, then the lower head is disposed between said carriers to expand said carriers, and next the lower head is cleared of saidcarriers and the upper head is disposed between said carries to collapse the latter, and means to advance said mandrel.

7 An expansible bit comprising a slotted body and a bore, cutter carriers fulcrumed in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads and a passageextending therethrough communicating With said bore, a check valve controlling said passage to prevent outflow of liquid, spaced cavities formed between carriers, then the lower head is disposed out and by said carriers belowthe' fulcrums of of the intermediate cavity and between said said carriers to accommodate the lower head, carriers with said upper head in the upper said heads being spaced so with relation to cavity to expand said carriers, and next the said carriers that with progressive advance lower head is disposed in the lower cavity of the mandrel toward the lower end of the and the upper head out of the upper cavity body the lower head is disposed in the upand between said carriers to collapse the latper cavity to enable collapsion of the-can ter, and means to advance said mandrel. riers with the upper head clear of said car- 5. An expansible bit comprisinga slotted riers, then the lower head is disposed bebody, cutter carriers pivoted intermediate of tween said carriers to expand said carriers their ends in said slots transverse of the drilland with the upper head clear of said caring axis of said bit so that their cutter ends riers, and next the lower head is disposed in maybe swung outwardly to expanded posisaid carriers tocollapse the latter, and means the lower cavity and the upper head between axially movable mandrel having upper andlower heads with their lower ends tapered,

to advance said mandrel.

8.'A.n expansible bit comprising a slotted three spaced cavities formed between and body and abore, cutter carriers fulcrumed by said carriers to accommodate said heads, in Said Slots r nsvers of the drilling axis of said bitso that their cutter ends may be said carriers so that with progressive adswung outwardly to expanded position and Vance of the mandrel toward the lower end inwardly to collapsed position, an axially of the body the lower head is disposed in the movable mandrel having upper and lower intermediate cavity and the upper head clear heads and a passage extending therethrough carriers, then the lower head is disposed out controlling said passage to prevent outflow of said intermediate cavity between said carof liquld, spacec cavities formed between 'riers and the upper head in the upper cavity and by said carriers, One 11 to accommodate head is disposed in the to expand said carriers, and next the lower a head, said cavities being spaced with relalower cavity and the t1on to said heads so that with progressive adupper head between said carriers to collapse Vance of the mandrel toward the lower end the latter, and means to advance said mandrel. of the body the lower head is disposed in a 6. An expansible bit comprising a slotted cavity to enable collapsion. of the carriers body and a bore 6 in said slots transverse of the drilling axis of then the lowerhead is disposed out of said a passage extending therethrough communisaid bit so that their cutter ends may be swung cavity between said carriers and below their outwardly to expanded position and inward- .fulcrums and the upper head is disposed in a 1y to collapsed position, an axially movable cavity to expand said carriers, and next the mandrel having upper and lower heads and lower head is disposed in a cavity and the upper head out of a cavity and between said cutter carriers fulcrumed with said upper head clear of said carriers,

carriers and above their fulcrums to collapse (tihe latter, and means to advance said manrel:

9. An expansible bit comprising a slotted body and bore, cutter carriers fulcrumed in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads and a passage extending therethrough communicating with said bore, a check valve controlling said passage to prevent outflow of liquid, three spaced cavities formed between and by said carriers to accommodate said heads, the two lower cavities being contiguous, said cavities being spaced so that with progressive advance of the mandrel toward the lower end of the body the lower head'is disposed in the intermediate cavity to enable collapsion of the carriers and the upper head clear of said carriers, then the lower head is disposed out of the intermedi ate cavity and between said carriers with said upper head in the upper cavity to expand said carriers, andnext the lower head is disposed in the lowercavity and the upper head out of theupper cavity and between said carriers to collapse the latter, and means to advance said mandrel.

10. An expansib'le bit comprising a slotted body and a bore, cutter carrierspivoted intermediate of their ends in said-slots transverse of the drilling axis of said bit so that their cutter ends may be swung outwardly vto expanded position and inwardly to collapsed position, an axially movable mandrel hav ng upper and lower heads with their "lower ends tapered, said mandrel having a passage extending therethrough communicating with said bore, a check valve controlling said passage to prevent outflow of liquid,

three spaced cavities formed between and by:

said carriers to accommodate said heads, said cavities being spaced with relation to said carrlers so that with progresslve advance of the mandrel toward the lower end of thebody the lower head is disposed in the intermediate cavity and the upper head clear of said carriers to enable collapsion of the carriers, then the lower head is disposed out of said intermediate cavity between said carriers and the upper head in the upper cavity formed between said carriers below their fulcrums to accommodate the lower head, said heads being spaced in relation to said carriers so that with progressive advance of the mandrel toward the lower end of the body the lower head is disposed in sald cavity to enable collapsion of the carriers, then the lower head is disposed between said carriers to expand said carriers, and next the lower head is cleared of said carriers and the upper head is disposed between said carriers to collapse the latter, and means to control advanceof said mandrel comprising a telescopic connector mounted on the upper end of said mandrel and axially slidable in said body, releasable means to'hold said connector in said body against downward move- .ment and permit limited downward movement of said mandrel to expansion position, and means to disengage said releasable means and permit said connector to follow said mandrel to collapsion position.

12. An expansible bit comprising a slotted body, cutter carriers fulcrumed in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads, spaced cavities formed between and by said carriers below the fulcrums of said carriers to accommodate the lower head, said heads being spaced so with relation to said carriers that with progressive advance of the mandrel toward thelower end of the body the lower head is disposed in the upper cavity to enable collapsion of the carriers With the upper head clear of said carriers, then the lower head is disposed between said'carriers to disengage said releasable means and permit of the mandrel toward the lower end of the body the lower head is disposedin a cavity to enable collapsion of the carriers with the upper head clear of said carriers, then the lower head is disposed out of said cavity between said carriers and below their fulcrums and the upper headis disposed in a cavity to expand said carriers, and next the lower head isdisposed in a cavity and the upper head out of a cavity and between said carriers and above their fulcrums to collapse the latter, and means to advance said mandrel, means to control advance of said mandrel comprising a telescoping connector mounted on the upper end of said mandrel and axially slidable in said body, releasable means to hold said connector in said body against downward movement and permit limited downward movement of said mandrel gagc said releasable means and ermit said connector to follow said man e1 to collapsion position.

l 14.'A'n expansible bit comprising a slotted "bodyfcutter carriers fulcrumed in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung,

outwardly to expanded'position, and inwardly to collapsed position, an axially movable mandrel having upper and lower heads, three spaced cavities formed between and by said carriers to accommodate said heads,

the two lowerpcavities being contiguous, said cavities being spaced so that with progressive advance of the mandrel toward the lower end of the body the lower head is disposed in the intermediate cavity to enable collapsion of the carriers and the upper head clear of said carriers, then the lower head is disposed out of the intermediate cavity andbetween said carriers with said upper head in the upper cavity to expand said carriers, and next the lower head is disposed in the lower cavity. and the upper head out of the upper cavity and between said carriers to collapse the latter, and means to control advance of said mandrel comprising a telescopic connector mounted on the upper end of said mandrel and-axially slidable in said 0 body, releasable means to hold said connector in said b y against downward movement and permit limited downward movement of said mandrel to expansion position, and

means to disengage said releasable means and ermit said connector to follow said man rel to collapsible position. "15. An expansible bit comprising a slotted body, cutter carriers pivotedintermediate .of their ends in said slots transverse of the drilling axis of said bit so that their cutter ends maybe swung outwardly to expanded position and inwardly to collapsed position,

a an axially movable mandrel having upper and lowerheads with their lower ends tathree spaced cavities formed between pered,

to expansion position, and means to disenfhead is cleared of said carriers and the upper and by said carriers to accommodate said heads, said cavities being spaced with relation to said carriers so that with progressive. advance of the mandrel toward the lower end of the body the lower head is disposed in the intermediate cavity and the upper head clear of said carriers to enable collapsion of the .carriers, then the lower head ,is disposed out of said intermediate cavity between saidcarriers and the upper head in the upper cavity to expand said carriers, and next the lower head is disposed in the lower cavity and the upper head between. said carriers to collapse the latter, and means to control advance of said mandrel comprising a; telescopic connector mounted on the upper end of said mandrel, and axially slidable in said body, releasable means to hold said connector in said body against downward mbvement and permit limited downward movementof said mandrel to expansion position, and means to disengage said releasable means and permit said connector to follow said mandrel to collapsion position.

16. An expansible bit comprisin a slotted body and a bore for connection to lrill pipe, cutter carriers fulcrumed in said slots trans- ,verse of the drilling axis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper andlower heads and a passage extending therethrough communicating with said bore, a check valve controlling said passage to prevent outflow of liquid, a cavity formed between said carriers below their fillcrums to accommodate the lower head, said heads being spaced in relation to said, carriers so that with-progressive advance of the mandrel toward the lower end of the body the lower head is disposed in said cav- 'ity to enable collapsion of the carriers, then the lower head is disposed between said car riers to expand said carriers, and the lower head is disposed between said carriers to collapse the latter, and means to control advance of said mandrel comprising a telescopic connector mounted on theupper end of said mandrel and axially slidable in said body, trip means to holdsaid connector in said body against downward movement and having trigger fingers projecting into the bore of said connector, said connector permitting downward movement of said mandrel to expansion position, and a plummet for passage through the circulation bore of the drill string and into the bore of said connector to engage said fingers and release said connector to permit the latter to follow said mandrel to collapsion position.

17. An expansible bit comprising a slotted body and a bore for connection to a drill pipe, cutter carriers ifulcrumed in said slots transverse of the drilling axis of said bit 130 so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads and a passage extending therethrough communicating with said bore, a check valve controlling said passage to prevent outflow of liquid, spaced cavities formed between and by said carriers below the fulcrums of said carriers to accommodate the lower head, said heads being spaced so with relation to said carriers that with progressive advance of the mandrel toward the lower end of the body the lower head is disposed in the upper cavity to enable collapsion of the carriers with the upper head clear of said carriers, then the lower head is disposed between said carriers to expand said carriers and with the upper head clear of said carriers, to expand said carriers and with the'upper head clear of said carriers, and next the lower head is disposed in the lower cavity and the upper head between said carriers to collapse the latter, and means to control advance of said mandrel comprising a telescopic connector mounted on the upper end of said mandrel and axially slidable in said body, trip means to hold said connector in said body against downward movement and having trigger fingers projecting into the bore of said connector, said'connector permitting downward movement of said mandrel to expansion position, and a plummet for passage through the circulation bore of the drill string and into the bore of said connector to'engage said fingers and release said connector to permit the latter to follow said mandrel to collapsion position.

18. An expansible bit comprising a slotted body and a bore for connection to a drill pipe, cutter carriers fulcrumed in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads and a passage extending therethrough communicating with sald bore, a check valve controlling said passage to prevent outflow of liquid, spaced, cavities formed between and by said carriers, one each to accommodate a head, said cavities being spaced with relation to said heads so that with progressive advance of the mandrel toward the lower end of the body the lower head is disposed in a cavity to enable collapsion of the carriers with said upper head clear of said carriers, then the lower head is disposed out of said cavity between said carriers and below their fulcrums and the upper head is disposed in a cavity to expand said carriers, and next the lower head is disposed in a cavity and the upper headout of a cavity and between said carriers and above their fulcrums to collapse the latte and means to control advance of said mandrel comprising a telescopic connector mounted on the upper end of said mandrel and axially slidable in said body, trip means to hold said connector in said body against downward movement and having trigger fingers projecting into the bore of said connector, said connector permitting downward movement of said mandrel to expansion position, and a-plummet for passage through the circulation bore of the drill string and into the bore of said connector to engage said fingers and release said connector to permit the latter to follow said mandrel to collapsion position.

19. An expansible bit comprising a slotted body and bore for connection to a drill pipe, cutter carriers fulcrumed in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads and a passage extending therethrough communicating with'said bore, a check valve controlling said passage to prevent outflow of liquid, three spaced cavities formed between and by said carriers to accommodate said heads, the two lower cavities being contiguous, said cavities being spaced so that with progressive advance of the mandrel toward the lower end of the body the lower head is disposed in the intermediate cavity to enable collapsion of the carriers and the upper head clear of said carriers, then the lower head is disposed out of the intermediate cavity and between said carriers with said upper head in the upper cavity to expand said" carriers, and next the lower head is disposed in the lower cavity and the tween said carriers to collapse the latter, and

means to control advance of said mandrel comprising a telescopic connector mounted on the upper end of said mandrel and axially slidable in said body, trip means to hold said connector in said body against downward movement and having trigger fingers projecting into the bore of said connector, said connector permitting downward movement of said mandrel to expansion position, and a plummet for passage through the circulation bore of the drill string and into the bore of said connector to engage said fingers and release said connector to permit the latter to follow said mandrel to collapsion position.

20. An expansible bit comprising a slotted body and a bore for connection to a drill pipe, cutter "carriers pivoted intermediate of their ends in said slots transverse of the drilling axis of said bit so that their cutter ends may be swung outwardly to expanded position and inwardly to collapsed position, an axially movable mandrel having upper and lower heads with their lower ends tapered, said mg trigger vent outflow of liquid, three spaced cavities formed between and by said carriers to accommodate said heads, said cavities being Spaced with relation to said carriers so that with progressive advance of the mandrel toward the lower end of the body the lowerhead is disposed in the intermediate cavity and the upper head clear of said carriers to enable collapsion of the carriers, then the lower head is disposed out of said intermediate cavity between said carriers and the upper head in the upper cavity to expand said carriers, and next the lower head is disposed in the-lower cavity and the upper head between said carriers to collapse the latter, and means to control advance of said mandrel comprising a telescopic connector mounted on the upper end of said mandrel and axially slidable in said body, trip means to hold said connector in said body against downward movement and havfingers projecting into the bore of said connector, said connector permitting downward movement ofi said mandrel to expansion position, and a plummet for passage through the circulation bore of the drill string and into the bore of said connector to engage said fingers and release said connector to permit the latter to follow said mandrel to collapsion position. i

In witness that I claim the foregoing I have hereunto subscribed my name this 12th day of April, 1930. J

GEORGE N.- FITCH. 

